Sewing machine with reciprocating work support means

ABSTRACT

Apparatus having a pallet for supporting a workpiece for movement relative to a tool. The pallet is removably mounted on moving means operative to move the workpiece on the pallet relative to the tool. The moving means comprise a movable support for the pallet, motive means, and a resilient, arcuate interconnection between the support and the motive means. The pallet has means for securing the workpiece against movement relative to the pallet and an aperture for providing tool access to portions of the workpiece where the tool operates on the workpiece.

United States Patent 1 Dorosz et al.

1 1 June 4, 1974 1 SEWING MACHINE WITH RECIPROCATlNG WORK SUPPORT MEANS[75] inventors: Adolph S. Dorosz, Beverly; Hans F.

Schaefer, Jr., Rockport; Gordon V. Sprague, Jr., Danvers, all of Mass.

[73] Assignee: USM Corporation, Boston, Mass.

[22] Filed: Jan. 29, 1973 {21 1 Appl. No: 327,846

Related US. Application Data [62] Division of Ser. No. 192.287, Oct. 26,1971.

[52] US. Cl. Ill/121.15, 112/260 [51] Int. Cl. D05b 21/00, D05b 75/00[581 Field of Search 112/260,215,216, 121.12,

[56] References Cited UNlTED STATES PATENTS 1.994150 3/1935 Meyers eta1. 227/143 X 2,633,816 4/1953 Johnson ct a1 112/260 X 2,992,431 7/1961Jensen 227/153 X 3,034,458 5/1962 Bennison Ill/121.12 3505,9615 4/1970Strothmann 3,557,442 1/1971 Spoiler 1. 227/153 X 3,557,727 1/1971Heimann 112/260 X Primary Examiner-James R. Boler Attorney, Agent, orFirm-Ralph D. Gelling; Vincent A. White; Richard B. Megley [57] ABSTRACTApparatus having a pallet for supporting a workpiece for movementrelative to a tool. The pallet is removably mounted on moving meansoperative to move the workpiece on the pallet relative to the tool. Themoving means comprise a movable support for the pallet, motive means,and a resilient, arcuate interconnection between the support and themotive means. The pallet has means for securing the workpiece againstmovement relative to the pallet and an aperture for providing toolaccess to portions of the workpiece where the tool operates on theworkpiece.

3 Claims, 6 Drawing Figures SEWING MACHINE WITH RECIPROCATING WORKSUPPORT MEANS This is a division of application Ser. No. 192,287, filedOct. 26, l97l.

BACKGROUND OF THE INVENTION Increasing costs of skilled labor haveprovided impetus over the last few years for increasing use of automaticdevices to replace costly, skilled labor. Similarly, automatic devicesto reduce the level of skill required to perform a particular industrialoperation have been introduced to reduce the cost of training andretaining operators qualified to perform the operation. Most recentlyefforts to automate industrial operations have been directed to morecomplicated tasks such as sewing, which operation had resistedautomation beyond the use of sewing machines because of the skillrequired to follow intricate patterns at high speed. Other similaruseful and decorative operations requiring intricate patterns such aspunching, leather tooling, embroidery and decorative stitching havesimilarly resisted automation.

Most recently, the advent of numerical and direct digital controls haveprovided readily programmable means for controlling movement aboutcomplicated patterns. Apparatus compatible with the speed and complexityof direction obtainable from such controls was therefore required. Wherethe workpieces to be operated upon in the apparatus are made ofrelatively hard material such as metal, the workpieces may be readilyand securely clamped for movement relative to operatinginstrumentalities of the apparatus. However, where the workpieces are ofsofter material such as wood, plastic, cloth or leather the workpiecesmay be damaged by the securing clamps. Moreover, where the workpiecematerials are particularly soft and floppy as with sheets of cloth orleather, accurate holding of the workpiece requires such a plurality ofclamps as to make changes between successive workpieces so difficult andtime-consuming as to vitiate the economicadvantage derived from thespeed of the automatic controls.

An alternative solution to moving the workpiece relative to the tool isto move the tool relative to the workpiece. However, where, as insewing, the operating instrumentalities require tools on both sides ofthe workpiece it is difficult and cumbersome to move the operatinginstrumentalities. Moreover, the operating instrumentalities andassociated mechanisms have substantial inertia due to their complexityand resultant weight. Accurate and rapid movement of such apparatus isdifficult.

SUMMARY OF THE INVENTION Accordingly, it is an object of the inventionto provide apparatus for rapidly and accurately moving a workpiecerelative to a tool which will permit speedy tive means. The pallet hasmeans for securing a workpiece on the pallet against movement relativeto the pallet so that the workpiece is accurately moved with the pallet.

In a preferred embodiment of the apparatus, the pallet has an aperturethrough a workpiece supporting surface of the pallet to provide toolaccess to both sides of a workpiece on the pallet. In another preferredembodiment, the apparatus has a holding tool on one side of a workpiececooperative with an operating tool on the other side of the workpieceand in aiding relation with the pallet for holding the workpiece againstmovement relative to the pallet.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features of theinvention will now be more particularly described with reference to apreferred embodiment which is intended to be only illustrative of andnot a limitation on the invention, it being understood that theinvention encompasses other embodiments than that described as preferredand illustrated in the accompanying drawings, in which:

FIG. 1 is a perspective view of a sewing machine having apparatus formoving a workpiece relative to a tool;

FIG. 2 is a perspective view of a portion of workpiece holding means ofthe machine in FIG. 1;

FIG. 3 is a perspective view of a portion of the workpiece moving meansof the machine shown in FIG. 1;

FIG. 4 is a perspective view of'a portion of the workpiece moving meansshown in FIG. 3;

FIG. 5 is a perspective view of a portion of workpiece holding means ofthe machine shown in FIG. I; and

FIG. 6 is a section view of the workpiece holding means of FIG. 5 with aworkpiece in place.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the preferred embodimentshown in FIG. 1, workpiece moving means generally at 10 are shownadapted for use with a lock stitch sewing machine 12 of a type longknown in the art. The sewing machine 12 is moditied in that thetraditional unidirectional, reciprocating feed dogs for moving a workpiece are replaced by the multidirectional workpiece moving means 10.The control 14 of a numerical or direct digital type well known in theart communicates with the moving means 10 to control movement of theworkpiece along predetermined paths having an intricacy and at a speedcommensurate with operation of the sewing machine. The workpiece movingmeans comprise a pallet 16 for supporting a workpiece (not shown) inoperative relation with the sewing machine. The pallet is disposed on apallet support 18 mounted for movement along a track 20. The track 20 isslidingly mounted on a cylindrical support 22 for bodily movement in adirection generally orthogonal to the track 20*. Axes of movement alongthe track and cylindrical support thus form a generally orthogonalcoordinate system usually denominated X and Y coordinates. respectively.The cylindrical support 22 is secured to a frame 24 of the machine 12.The workpiece supporting pallet 16 is thus mounted for movement relativeto the machine 12 in any direction comprised of vector components in theX and Y directions.

The sewing machine 12 has a reciprocating needle 30 cooperative withother stitch forming instrumentalities of the machine to form stitchesin the workpiece on the pallet. In forming stitches, the needle 30periodically penetrates the workpiece to draw thread (not shown) throughthe workpiece to form a stitch. To permit passage of the needle, thepallet 16 has an aperture 32 over which a workpiece is located andthrough which the needle may pass to form stitches in the workpiece.Penetration of the workpiece by the needle causes the workpiece tovibrate or ripple in timed relation to needle penetrations. The ripplingof the workpiece is commonly called flagging because of its resemblanceto the ripples of a flag blown by wind.

Flagging undesirably introduces contours into the workpiece which mayaffect the appearance of stitches subsequently formed in the workpiece.Additionally, flagging tends to vibrate or walk a workpiece in relationto the workpiece supporting pallet 16. Movement of the pallet will thusnot accurately correspond to movement of the workpiece. To overcome thisspecific workpiece moving problem, the apparatus has a workpiece holdingtool 32 seen in FIG. 2. The holding tool is mounted beneath the palletR6 for reciprocating movement in timed relation with the needle 30. Theholding tool has an aperatured nipple 34 in spaced alignment with theneedle for receiving the needle and of a height above a base 36 of thetool corresponding to a thickness of the pallet I6. The tool 32 ispivotally mounted on a frame of the machine 12 by pivot 38 and connectedat an opposite end by link 40 to an eccentric 42 secured to an end ofarotating drive shaft 44 of the type traditionally employed to drive feeddogs in a lock stitch sewing machine. Accordingly, rotation of the driveshaft 44 which occurs in timed relation to reciprocating movement of theneedle is effective through the eccentric and link to raise the holdingtool 32 toward the pallet I6 and workpiece (not shown) thereon as theneedle penetrates the workpiece. The eccentric is positioned so that thebase 36 of the tool rises'into close proximity with a bottom 46 of thepallet 16 with the nipple 34 in close proximity to the underside of aworkpiece (not shown) on the pallet. The workpiece is thus supportedagainst downward move ment in response to needle penetration by an uppersurface of the nipple 34. The workpiece holding tool thus prevents theworkpiece from flagging and aids in holding a workpiece against movementon the pallet. Downward movement of the holding tool 32 corresponds withupward movement of the needle to release the workpiece for movement withthe pallet. The holding tool thus does not interfere with the unitarymovement of the workpiece and pallet.

As seen in FIG. 3 the pallet support l8 has a toothed rack 50 secured toone edge of the support to and cooperative with a toothed pinion (notshown) on a rotatably driven shaft ofa motor 52 mounted on a sleeve 54also supporting the track and pallet support 18 for sliding movementalong the cylindrical support 22. A second rack 56 is secured to thesleeve 54 and cooperates with a toothed pinion (not shown) on arotatably driven shaft of a second motor 58. The motor 58 is secured tothe frame 24 of the moving means. Rotation of the pinions by the motors52 or 58 is thus effective to drive the racks and connected membersalong the X or Y axes of movement. Because the racks 50 and 56 aresecured to one movable member and their respective drive motors and 58are secured to another member. the pinions on the motors and the racksmay be subject to disengagement such could cause the racks and pinionsto jam or skip or otherwise fail to properly cooperate. To avoid suchproblems without rigorous mounting, the racks and 56 are secured ateither end to their respective members by a resilient coupling link 60.

The coupling link is shown in greater detail in FIG. 4. Because all thecouplings are identical only one on rack 50 will now be described. Thecoupling comprises a leaf spring 62 secured at one end to a surface 64of the rack 50 and at the other end to a surface portion 66 of themovable pallet support 18. The surfaces 64 and 66 do not engage eachother but are substantially aligned and of sufficient size to provide abase against which the spring 62 may flex. The surfaces 64 and 66 alsocooperate with securing means such as bolts 68 to permit the spring 62to pivot about the bolts. The surfaces 64 and 66 are sufficientlyclosely spaced so that flexure of the spring will be substantiallynormal to the surfaces 64 and 66. Spring flexure thus has substantiallyno component parallel to the surfaces 64 and 66 which would permitlongitudinal displacement of the rack in relation to the support 18.Similarly, a second surface 70 of the support 18 adjacent and normal tothe surface 66 cooperates with the pivotally secured spring 62 to permitonly a limited amount of pivotal movement so that substantially all thepivotal movement of the spring is in a direction normal to the surface70. Longitudinal displacement of the rack 50 in relation to the support18 is thus again avoided to insure accurate orientation of the rack inrelation to the support. The coupling 60 thus accurately but flexiblyconnects the rack to the support. The flexible connection permits therack to assume positions slightly out of alignment with the support tocompensate for misalignment between the support to which the rack isconnected and the pinion of the motor in toothed engagement with therack. Forces applied by the pinion to the rack are sufficient to drivethe rack out of alignment with the support and into alignment with thepinion.

As seen in FIG. 5 the pallet 16 for supporting a workpiece is connectedat one end to the movable pallet support I8 and is slidingly supportedat the other end by a table of the sewing machine 12. A side of thepallet 70 adjacent the movable pallet support means 18 has projections72 having holes 74 cooperative with locating pins 76 to accuratelyposition the pallet 16 in relation to the pallet support 18. To insurecontinued cooperation of the holes 74 and projections 76 the movablepallet support is provided with spring clamps 78 which engage the palletprojections 72 in an operative position and may be removed from thepallet projections in an inoperative position, shown in phantom. Theclamps 78 are secured to the movable pallet support 18 by springs 80which urge the clamps into engagement with the pallet projections.

The pallet 16 comprises spaced plates 82 and 84 in parallel planesconnected about interior and exterior peripheries by sealing and spacingmembers 86 and 88 respectively. In a preferred embodiment theprojections 72 of the pallet are a part of the exterior sealing andspacing member 88. The interior spacing member 86 is contiguous with theperimeter of the aperture 32 through which the needle 30 of the stitchforming instrumentalities penetrates a workpiece (not shown) placed on asurface of plate 82 of the pallet. Plate 82 is additionally providedwith a raised locating guide 90 against which a portion of a workpiecemay be placed to accurately position the workpiece in relation to theaperture 32. The plate 82 is also provided with a workpiece holdingaperture or apertures 92 for holding a workpiece against movementrelative to the pallet. A vacuum is supplied to the space between palletplates 82 and 84- by a vacuum coupling 94 on the plate 82. Vacuum iscontained within the pallet by the sealing and spacing members 86 and 38but flows through the apertures 92 to hold a workpiece on the plate 82with a suction of the vacuum. The workpiece holding apertures 92 thussecure the workpiece against movement relative to the pallet 16.

To further secure the workpiece against movement relative to the pallet16, the apertures 92 are provided with peripheral projections 96 as seenin FIG. ti. A workpiece 98 is raised above the surface of the palletsheet 82 by the projection 96 and drawn into the workpiece holdingaperture 92 by the vacuum. At the aperture 92 the workpiece thus adoptsa curved configuration in securing relation with the plate @2 of thepallet.

in another embodiment of the invention (not shown) both upper and lowerplates 82 and 8d of the pallet may be provided with workpiece securingapertures. In one use of this embodiment a workpiece may be secured tothe upper and lower surfaces of the pallet as described for the plate @2above. In another use of the alternative embodiment an additional sheetof material impervious to the vacuum and of corresponding shape to thelower plate 84 ofthe pallet may be placed in engagement with the lowerplate to maintain the vacuum in the pallet. The additional sheet may beprovided with an adhesive to prevent its disengagement from the lowerplate when removal of a workpiece from the upper plate reduces thevacuum in the space between the sheets of the pallet. The object of thisalternative embodiment is to permit right and left handed parts ofcorresponding shape to be sewn on a single pallet configuration much asdouble edged dies are used to cut right and left handed parts in diecutting.

The apertures 32 and 92 may be cut in the sheets of the pallet by apattern changing device of' the type described in copending UnitedStates patent application Ser. Nov 83,830, filed Oct. 26, i970, in thename of Edward H. Sonn et al.

Having thus described our invention what we claim as new and desire tosecure by letters Patent of the United States is:

ii. In a sewing machine having a reciprocating needle and a needlereciprocating mechanism, a holding tool for supporting the workpiececomprising:

A. an apertured nipple which is mounted for reciprocating movement intosupporting engagement with the workpiece, the nipple aperture beingsubstantially axially aligned with the needle during workpieceengagement; and

B. reciprocating nipple drive means operatively connected to said needlereciprocating mechanism to cause the nipple member to intermittentlyengage the workpiece in timed relation to needle penetration of theworkpiece.

2. ln a sewing machine having a reciprocating needle.

a holding tool for supporting the workpiece as de' scribed in claim 1wherein the apertured nipple is mounted on a support arm, said arm beingpivotally mounted to provide reciprocating movement of the nipple intosupporting engagement with the workpiece.

B. means connected to the eccentric for causing rotation thereof in amanner that provides for supporting engagement of the holding toolduring needle penetration of the workpiece.

l i l

1. In a sewing machine having a reciprocating needle and a needlereciprocating mechanism, a holding tool for supporting the workpiececomprising: A. an apertured nipple which is mounted for reciprocatingmovement into supporting engagement with the workpiece, the nippleaperture being substantially axially aligned with the needle duringworkpiece engagement; and B. reciprocating nipple drive meansoperatively connected to said needle reciprocating mechanism to causethe nipple member to intermittently engage the workpiece in timedrelation to needle penetration of the workpiece.
 2. In a sewing machinehaving a reciprocating needle, a holding tool for supporting theworkpiece as described in claim 1 wherein the apertured nipple ismounted on a support arm, said arm being pivotally mounted to providereciprocating movement of the nipple into supporting engagement with theworkpiece.
 3. In a sewing machine having a reciprocating needle, aholding tool for supporting the workpiece as described in claim 2wherein the reciprocating drive means comprises: A. an eccentricallymounted cam member operatively connected to the pivoting support arm;and B. means connected to the eccentric for causing rotation thereof ina manner that provides for supporting engagement of the holding toolduring needle penetration of the workpiece.